Grinding-mill



3 Sheets-Sheet 2.

(Model.)

0. U. GRANDALL.

GRINDING MILL.

No. 248,292. Patented 001;. 18, 1881.

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WITNESSES:

n. Prrms. Pholo-Lkhognpher. Washingbn, 04 a (Model) Q a Sheets-Shet a.

v C. I]. GRANDALL.

GRINDING MILL.

No. 248,292. Patented 001;.18, 1881.

fi aaafuc 6 Nv PLIEns, Mme-mm I UNITED STATES PATENT OFFICE.

- GYPRIAN U. ORANDALL, OF STERLING, ILLINOIS.

GRINDING-MILL.

SPECIFICATION forming part of Letters Patent No. 248,292, dated October18, 1881.

Application filed April 22, 1881. (ModeL) To all whom it may concern Beit known that I, CYPRIAN U. URANDALL,

a citizen of the United States, residing at Sterling,.in the county ofWhitesides and State of Illinois, have invented certain new and usefulImprovements in Grinding Mills; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being had to the accompanying drawings, and toletters or figures of reference marked thereon, which form a part ofthis specification.

My invention has reference to certain improvements in grinding-mills;and it consists in the features hereinafter mentioned.

The object of my invention is to furnish, in

adoublg mill, a divider which shall unerringly lower halves of thejacket; Fig. 5, a central transverse vertical section through themachine.

A is the bench supporting the mill.

B is a frame, placed on the bench Av to support the hopper and screeningapparatus.

0 is an ordinary-hopper, into which the grain to be ground is placed.

D is a screen,which atits upper end is placed under and receives thegrain from the hopper O, and at its lower end is supported adj ustablyby means of the strap a, passing from the sides of the screen throughthe roller 1). By twisting the roller b the lower end of the screen D israised and lowered at will. The upper end of the screen D is pivoted inany suitable manner, and its lower end vibrates laterally. Such motionis imparted to the screen D by means of an arm, 0, pivpted at one end onthe side and near the lower end of the screen D, the other end of thearm 0 being pivoted to the upper end of the oscillating lever 07, whichlatter is pivoted near its center on the cross-beam e,

ing corrugated surfaces, and being placed suf-,

ficiently near each other to crack or partially grind the grain as thelatter passes downward between the two adjacent sides of such rollers.

The roller E is revolved by pulley or cog-wheel affixed to one end ofits axle, and can be turned 1 by hand or run by a horse or other power.The rollers are revolved toward each other at their tops by means of thesmall cog-wheelsg g. I find by experiment that the grinding is done morerapidly when one of the rollers is run at a higher rate of speed thanthe other, and I have therefore varied the diameter of the engagingcog-wheels g 9, so that the roller F may run at a greater velocity thanthe roller E. 1,.

G is a divider, having the duplex, corrugated, and elliptically-concavedfaces h h, which refeed the preliminarily-cracked grain againstthelowerpartof the grinding-rollers EF. The

grinding-faces h h of the divider G are concaved elliptically ratherthan circularly, and by means of such peculiar conformation the faces hh gradually approach the grindingrollers from the feed to the dischargeend, thus greatly accelerating the grinding process. I

make the center crown of the divider G flat, and wide enough to retainquite an amount of meal, and utilize the meal accumulating thereon indiverting the partially-ground grain under the respectivegrinding-rollers, because I find, in view of the fact that one rollertakes feed faster than the other, that no mechanical device will form sotrue a center between the rollers E F as the falling meal itself. Thedivider G is provided with lateral tenons r r,

centrally located, which fit into corresponding recesses ss in the lowersides of the jacket H, and thus hold the divider from end movement. Ineach recess 8, and over the tenon r, I place the spring t, which servesto hold the divider down to its point of adjustment.

The divider G is supported by the table I,

having the four inclined bases t i t 1', each of which latter rests upona shelf, j, cast on the inner side of the lower part of the jacket H,such. shelves having an inclined upper surface.

By means of the screw-bolt K the table I is drawn or pushed down on theshelves j, and thus the divider G is raised or lowered so as to grindcoarse or fine, as may be desired.

On the inner surface of the upper half of the jacket H, and at the endsof the rollers E F, are formed the annular recesses 70 k, which receivethe ends of the rollers E F and permit the inner face of the jacket H toproject over the ends of the rollers E F, and thus prevent the passageof any partly-ground meal between the ends of the rollers E F and theinner faces of the jacket H, where, in the ordinary horizontal roller,it is apt to collect and pack and heat. The sides ofthe upper part ofthe jacket H are contracted to give the recesses k k depth. This permitsthe grain to spread the width of the grinding-rollers without crowdingaround the ends.

As the lower halfof the r0llers,when running at as high rate of speed asit is necessary to run. these small rollers, are apt to carry up part ofthe meal behind the ends of the rollers, to prevent this, and also toprovide a ready exit for all meal working around the lower half of theends of the rollers E F, I cut away the inner surface of thejacket H,opposite the lower h alf of the ends of such rollers, forming theoutwardly-receding walls I l.

The operation of my mill is as follows: The grain placed in thehopperOpasses down therefrom through the screen D, between the grinding-rollersE F. There the grain is preliminarily cracked or broken, the rollers notbeing set so close to each other as to grind into meal or flour. Afterthis first process the material falls upon the flat crown of the dividerG, where it soon accumulates into a ridge, down the respective sides ofwhich the material passes to the grindin g concave faces h, inproportion to the rapidity of the grinding of the respective sides. Theroller F, by reason of its greater velocity, disposes of and draws morematerial than the slower-revolving roller E; and as a metal ridge wouldbe fixed and arbitrary, I substitute the ridge of meal, which causes thematerial to fall the fastest to that side on which there is the greatestexhaustion. As the feed ends of the grinding-faces of the divider Gr areset farther from the rollers than the discharge ends, the materialpasses into a narrow chamber as it is reduced in size, and the grindingis gradual over the whole of the faces h It. By turning the screw-bolt Kthe divider is set to or from the rollers. The meal is dischargedoutwardly from both sides of the divider, but is gathered by thejacket Hinto the discharge-spout at the bottom.

I deem the screen D of great importance. The grindingrollers are made ofhard iron to avoid wear, and are therefore liable to have theircorrugations broken by the interposition of any hard substance. Ingrinding corn often pieces of nails, small gravel, &c., are shoveled up.The screen D effectually prevents such, as well as silk and husks, frompassing to the cylinders. The screen has also the functions ofdistributing the grain the full length of the grinding-face of therollers.

What I claim as my invention. and desire to secure by Letters Patent ofthe United States,

1. The cylinders E F, in combination with the divider G, the latterbeing provided with a flat crown or truncated apex to serve as a benchto receive the falling meal, so that the latter may form its own line ofdivision, substantially as and for the purpose mentioned.

2. The combination, with the rollers E F, of the divider Gr, having aflat crown or truncated apex, and duplex corrugated andellipticallyconcaved faces h h, substantially as and for the purposesherein shown and described.

In testimony whereof I affix my signature in presence of two witnesses.

C. U. GRANDALL.

Witnesses:

JOHN W. NILEs, SYDNEY T. OSMER.

